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Oldest Water on Earth Found Deep Within the Canadian Shield

A scientist takes a sample of water from a mine deep underground in Ontario, Canada (2013)
Photo credit:
B. Sherwood Lollar et al.

University of Toronto scientists one up themselves by finding 2 billion-year-old water, half a kilometer deeper than the 1.5 billion-year-old stuff.

In 2013, researchers from the University of Toronto discovered water that was about 1.5 billion years old. At that time, it was the oldest water found on Earth. Some members of the original team working in the same Canadian copper, zinc, and silver mine, near Timmins, Ontario, have now found a deeper source of water—and it’s at least 500,000 years older than the previous find.

On December 13, geoscientist Barbara Sherwood Lollar presented “New Frontiers for Deep Fluids and Geobiology Research in the World's Oldest Rocks” at the Fall Meeting of the American Geophysical Union. Sherwood Lollar and her colleagues have studied the deep hydrosphere for several decades in mines around the world, and in her presentation, she referred to the Kidd Creek mine, on the Canadian Shield, as an “iconic site.”

The fracture water discovered in 2013 was found at a depth of 2.4 kilometers (1.5 miles) below the surface, and Sherwood Lollar told BBC News that “It really pushed back our understanding of how old flowing water could be, so it really drove us to explore further.”

The newest investigation was led by Dr. Oliver Warr, also from the University of Toronto. The study took advantage of the fact that mine exploration was drilling deeper into the Precambrian rocks of the Canadian Shield, and the most recently discovered water was found at a depth of 3 kilometers (1.9 miles).

The scientists derived the resident time, or “age,” of the water through an analysis of gasses dissolved in the fluid. Previous research of air trapped within ancient rocks found that noble gasses such as helium, neon, argon, and xenon occur in distinct ratios linked with certain eras of Earth’s history. Ancient water flowing through fractured rock can become trapped deep in the crust, preserving evidence of the conditions present when it was isolated.

BBC News reported that the scientists also found chemical traces left behind by single-celled organisms that once lived in the fluid. Sherwood Lollar said that “By looking at the sulphate in the water, we were able to see a fingerprint that’s indicative of life.” Adding that “This has to be an indication that organisms have been present in these fluids on a geological time scale.”

The researchers believe that a better understanding of Earth’s geobiology would help us understand how life adapts to extreme conditions on Earth. It could also help us identify potential limits to life on this planet—and others.